tbd.pi
Posts: 34
Joined: Sat Aug 11, 2012 11:21 am
Location: NJ,USA
Contact: Website

Local Pi->* Communication

Fri Oct 10, 2014 9:00 pm

I'm working on a project with my daughter for Halloween. I want to automate the movement of Halloween decorations. So, with the help of Joan, pigpio and some very helpful members I have managed to get multiple servos working, I've figured out how to get motion sensors (working on range sensor), LEDs etc working (I'll put a lot more effort into learning more about everything I've done later)

As my 5 year old is the brains behind the operation, we have come up with some pretty creative ideas. What's she's describing takes it beyond simple motion sensing triggering movement! What I want to do is be able to have multiple devices able to communicate, so if I have a device with a motion sensor at the end of the path and on the lawn to the other side, things closer to my door can know what is approaching and from where.

My thought is to have multiple pis (I have an A and 2bs) running off battery packs (also have a beaglebone and Arduino Uno if they can play in there) with the right sensors communicate back to the device that's in control of servos, lights etc. But, I'm not running Ethernet across my lawn and having hubs sat outside, so I was wondering if there was any recommendations on how to make devices wirelessly communicate. I've seen these little RF modules on Amazon for like $5, ZBee? My front lawn is about 75ft by 25ft so all the devices would be somewhere in there. I'm a developer, so I'm not afraid of any coding necessary and I have an open budget (within reason, I want to continue my marriage after the projects credit card bill comes in)

If I can't quite get this rather ambitious project done in time for Halloween, I'll scale it back to basic motion sensing and move on to Christmas, but I am enjoying time spent coming up with crazy ideas with my daughter, so I'm going to try and would appreciate any and all ideas.

Thanks

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aTao
Posts: 1087
Joined: Wed Dec 12, 2012 10:41 am
Location: Howlin Eigg

Re: Local Pi->* Communication

Fri Oct 10, 2014 9:51 pm

Easiest way is to have 1 server RPi connected to the "broadband" or internet socket on a WiFi router.
Then any WiFi enabled devices in range can talk to the server (only, unless you dig around in the routing of the router, WiFi -> WiFi is not normally enabled)
Then a web server with Python (on the RPi) can manage all the overseeing you want.
>)))'><'(((<

tbd.pi
Posts: 34
Joined: Sat Aug 11, 2012 11:21 am
Location: NJ,USA
Contact: Website

Re: Local Pi->* Communication

Sat Oct 11, 2014 11:10 am

I read my question now and I realize that it's pretty obvious, the wireless network route! I guess my brain wasn't going there because I was really thinking about independence from my home (and not pointing that out), because my daughters teacher has expressed an interest in seeing the end result. If I wanted to do this without having devices on my local WiFi network, is this possible?

User avatar
aTao
Posts: 1087
Joined: Wed Dec 12, 2012 10:41 am
Location: Howlin Eigg

Re: Local Pi->* Communication

Sat Oct 11, 2014 12:06 pm

tbd.pi wrote:I read my question now and I realize that it's pretty obvious, the wireless network route! I guess my brain wasn't going there because I was really thinking about independence from my home (and not pointing that out), because my daughters teacher has expressed an interest in seeing the end result. If I wanted to do this without having devices on my local WiFi network, is this possible?
Sure, just get another router, set SSID to something obvious, remember to enable security and even hide the network, and set the Halloween system to use that and only that network.
>)))'><'(((<

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

Re: Local Pi->* Communication

Mon Oct 13, 2014 9:20 am

WIFI routers are cheap these days, I use this one as both a battery for the pi a and communications device (despite calling itself 3g it doesn't actually have any native access to the mobile networks). You can connect it to one of the Pi's by Ethernet cable, reducing the number of WIFI dongles you need to buy.
Doug.
Building Management Systems Engineer.

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